That's a wild oversimplification of the recent research into this topic. The PURE study in 2014 found no benefit to blood pressure beyond limiting to a moderate level (I can't remember number off habd, but assume a reasonable 2 grams or so). The AHA is still recommending moderation.

It's not a function of it being a long duration study. It is a function of the designated. Itself. Food diaries are notoriously not a reliable means to measure intake. But for example having a patient come in for weighings by research stuff in a controlled methodology over an extended period is a reliable means to follow weight over the long term

I did JFK->Santiago->IPC->Lima->Buenos Aires--> JFK for 40,000 BA points 4 years ago. We convinced the phone agent it was a single round trip JFK to IPC, and Buenos Aires was a direct line of return (she clearly didnt know geography). After that, 2 friends called in requesting the same itinerary and were granted it.

Churning related,but not a credit card issue:
I have a month until my southwest vouchers expire (3 x $200) worth, and dont have any trips between now and then. Is there a way to extend them? The SW site states that sold or bartered vouchers are voided, so I'm not sure of the feasibility of those routes. The extension fee would be $100 per voucher, so not a great option